U1650

DTC U1650

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.



DTC Descriptor
DTC U1650
- Steering Wheel Sensor CAN Malfunction




Diagnostic Fault Information






Circuit Description

The controller area network (CAN) serial data circuit is a high speed serial data bus used to communicate information between the steering angle sensor and the electronic brake control module (EBCM). When the ignition switch is turned to the ON position, the module and the steering angle sensor begin to transmit data between each other.


The CAN bus circuit is monitored continuously after the ignition switch is turned to the ON position.


Conditions for Running the DTC

* The ignition is ON.
* The vehicle speed is greater than 40 km/h (25 mph).



Conditions for Setting the DTC

Line Interuptions are detected by the CAN message monitor.


Action Taken When the DTC Sets

If equipped, the following actions occur:

* The EBCM disables the traction control system (TCS)/vehicle stability enhancement system (VSES) and for the duration of the ignition cycle.
* A malfunction DTC will set.
* The Stability indicator turns ON.



Conditions for Clearing the DTC

* The condition for the DTC is no longer present and the DTC is cleared with a scan tool.
* The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.



Diagnostic Aids

Possible causes of this DTC are as follows:

* CAN HI and CAN LO circuits shorted together
* CAN HI or CAN LO circuit shorted to ground
* CAN HI or CAN LO circuit shorted to voltage



Reference Information
Schematic Reference

Antilock Brake System Schematics ([1][2]Antilock Brakes / Traction Control Systems)
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information.


Circuit/System Verification

Important: With a DMM, test the GM LAN Bus+ and GM LAN Bus- circuits between the EBCM and the steering angle sensor for being shorted together, shorted to voltage, and shorted to ground.



1. With the scan tool perform the Steering Angle Sensor Centering procedure in EBCM VSES scan tool special functions.

• If the steering angle sensor procedure is not successful, test or replace the steering angle sensor.

2. Test drive the vehicle refer to Diagnostic Test Drive (Description of On-Board Diagnostics) .

• If DTC U1650 resets, test or replace the EBCM.




Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Diagnostic Test Drive (Description of On-Board Diagnostics)
* Steering Angle Sensor Centering (Procedures)
* Steering Wheel Position Sensor or Steering Shaft Lower Bearing Replacement (Steering Wheel Position Sensor or Steering Shaft Lower Bearing Replacement)
* Control Module References (Programming and Relearning)for EBCM replacement, setup, and programming